6bra questions and loads (n-140)

[Matt_3479]

So I finally purchased my first 6br variant (6bra). First off I’m wondering if it’s better to get alpha brass or Lapua and fire form. I don’t care either way but curious which has proven to be better brass as both are fantastic companies.

secondly, with h-4895 and varget being so difficult to find, how is n140 making out with 105’s? If so what would be starting load? What load is good for fireforming

 

[Jdne5b]

There's a thread a few pages back with some n-140 info in it. I just did a little break in on a PRS rifle in 6BRA with N140. In Lapua brass already BRA formed in another rifle these were my approx speeds in a new 26 inch barrel and 105 Hybrids:

30.6 - 2820
30.8 - 2845
31.0 - 2855
31.2 - 2875
31.4 - 2910

No pressure signs, easy bolt lift. I'm going to load a hundred at 30.9 and see what the velocity looks like after those are all fired. If I needed to fireform, I'd probably load the 29.6-30.0 range for a lighter load.

I don't think you would go wrong with any of the 6BR brass. Alpha, Peterson or Lapua.

 

[Matt_3479]

I read through a few 6bra threads and very little data with the n140. I know I can get vihtavouri powders and have 140 on hand for my 223 with 70’s and 80’s. It would be nice to just buy a bulk and share the powder.

I was originally planning on going with alpha for the ease of it, but Lapua is cheaper and it’s tough to beat Lapua brass.

 

[DaleTN]

I fired one shot per load yesterday evening just to get us some more data.
28" barrel 105gr BRA with new Alpha brass
31.1 - 2925
31.2 - 2934
31.3 - 2929
31.4 - 2942
31.5 - 2953

I may continue with 31.6 and up next week if I find the time. I still have some new cases to shot to keep the variables as consistent as possible.

 

[TylerFromMS]

It’ll be very happy at 31.5 under a 105 hybrid. I’ve used it exclusively for a couple of years in my bra with Lapua. I’ve played around with the Alpha a little, and it seems like a little less charge for same speed out of a 30” barrel.

Unrelated, but the Alpha can be taken to 3100 without pressure with a 105.

 

[Matt_3479]

It’ll be very happy at 31.5 under a 105 hybrid. I’ve used it exclusively for a couple of years in my bra with Lapua. I’ve played around with the Alpha a little, and it seems like a little less charge for same speed out of a 30” barrel.

Unrelated, but the Alpha can be taken to 3100 without pressure with a 105.

that just seems insane. 3100 without pressure!!

i like the idea of plug and play with the alpha brass but realistically you should fireform to chamber regardless, so at that case then it doesn’t make a different with Lapua and at 40 dollars cheaper per 100 it seems good.

i shoot alpha in 2 chambering now, but not the ocd brass

 

[TylerFromMS]

Lapua and at 40 dollars cheaper per 100 it seems good.

I mean, $25 and you get an aesthetic smoke grey 100 round mtm box. And a note from some guy named Tom. I've never seen Lapua at $85 I don't think.

You need to get the ocd brass. It's really good.

 

[Matt_3479]

I mean, $25 and you get an aesthetic smoke grey 100 round mtm box. And a note from some guy named Tom. I've never seen Lapua at $85 I don't think.

You need to get the ocd brass. It's really good.

in Canada I can get lapua for 115-120 and the alpha ocd for 159.99

 

[TylerFromMS]

Canada

 

[DaleTN]

Finally got around to shooting and posting the next 5 (I’ve been forgetting)
31.6 - 2962
31.7 - 2977
31.8 - 2976
31.9 - 2989
32 - 3002

maybe the info will help you some

 

[Matt_3479]

Finally got around to shooting and posting the next 5 (I’ve been forgetting)
31.6 - 2962
31.7 - 2977
31.8 - 2976
31.9 - 2989
32 - 3002

maybe the info will help you some

Thank you.
I’m hoping to get out this week as well to get playing a bit. My fireform load is 2850fps currently.

 

[Sumtoc]

Trying N140 in my new (about 250 rounds now) 6BRA. N150 just didn't seem predictable and I have lots of N140 so decided to give it a whirl. My 3 shot averages out of a 28" barrel seem pretty fast and so far no standout node. These are Berger 105 VLDs, Alpha brass, Remington 7 1/2 primers (I have more of those than any other by far so trying to make them work). Jumping them .015" for this rough OCW test, 3 shot averages:
30.0 - 2888
30.3 - 2915
30.6 - 2940
30.9 - 2971
31.2 - 3004
31.5 - 3040
31.8 - 3066
A little primer flattening in the last load but the bolt lift was normal and the brass looked Ok. I had 3 more loaded with 32.1 gr but decided not to shoot them. I thought the accuracy node was around 2920 but
the SD and ES was best at 31.2/3004, so I'll load 5 each at .1 gr two steps above and below and see if I can confirm a good node.

My question is about the speed. Using a LabRadar so I guess I can trust it but just seems awful fast at these charge weights. Thoughts?

 

[Matt_3479]

Trying N140 in my new (about 250 rounds now) 6BRA. N150 just didn't seem predictable and I have lots of N140 so decided to give it a whirl. My 3 shot averages out of a 28" barrel seem pretty fast and so far no standout node. These are Berger 105 VLDs, Alpha brass, Remington 7 1/2 primers (I have more of those than any other by far so trying to make them work). Jumping them .015" for this rough OCW test, 3 shot averages:
30.0 - 2888
30.3 - 2915
30.6 - 2940
30.9 - 2971
31.2 - 3004
31.5 - 3040
31.8 - 3066
A little primer flattening in the last load but the bolt lift was normal and the brass looked Ok. I had 3 more loaded with 32.1 gr but decided not to shoot them. I thought the accuracy node was around 2920 but
the SD and ES was best at 31.2/3004, so I'll load 5 each at .1 gr two steps above and below and see if I can confirm a good node.

My question is about the speed. Using a LabRadar so I guess I can trust it but just seems awful fast at these charge weights. Thoughts?

That does seem quick but could be wildly fast barrel. My current 20 tac is sporting a much faster then usual barrel.

I’m hoping to get out this week to start a pressure test on the bra and find out my speeds with n140.

 

[MikeMcCasland]

Trying N140 in my new (about 250 rounds now) 6BRA. N150 just didn't seem predictable and I have lots of N140 so decided to give it a whirl. My 3 shot averages out of a 28" barrel seem pretty fast and so far no standout node. These are Berger 105 VLDs, Alpha brass, Remington 7 1/2 primers (I have more of those than any other by far so trying to make them work). Jumping them .015" for this rough OCW test, 3 shot averages:
30.0 - 2888
30.3 - 2915
30.6 - 2940
30.9 - 2971
31.2 - 3004
31.5 - 3040
31.8 - 3066
A little primer flattening in the last load but the bolt lift was normal and the brass looked Ok. I had 3 more loaded with 32.1 gr but decided not to shoot them. I thought the accuracy node was around 2920 but
the SD and ES was best at 31.2/3004, so I'll load 5 each at .1 gr two steps above and below and see if I can confirm a good node.

My question is about the speed. Using a LabRadar so I guess I can trust it but just seems awful fast at these charge weights. Thoughts?

Those charge weights are fast, but it's Alpha brass so the capacity is going to be lower. I believe you can trust the LabRadar too.

Here's my N140 Data (105 Hybrids, GM205M, Lapua brass)
30.5 - 2847
30.7 - 2865
30.9 - 2885
31.1 - 2898
31.3 - 2917
31.5 - 2937

These data points were taken at ~75 deg, out of a 30" BRA tube.

 

[Sumtoc]

Never found a node in the higher velocities posted earlier. As with others it seems happiest around 2910-2920 FPS. Fired today, N-140, Berger 105 VLD, .015 jump, Alpha brass, Remington 7 1/2 primers, 5 shots per charge:
Charge Velocity SD ES
30.1 gr 2905 5 12
30.2 gr 2910 2 5
30.3 gr 2922 3.5 8
30.4 gr 2931 7 17
30.5 gr 2948 9 25

Groups were better in the lower range, first 3 shots were literally one hole @145 yds, then my mishandling factored in. But the groups for the last 2 charges had a lot of vertical stringing. Too much to be the shooter.

I'll load at 30.2 gr and then fine tune seating depth. Heading in towards touch and touch +. Now if I could just learn to shoot from a rest reliably I might be able stop wearing out this new barrel with tests........

 

[Matt_3479]

I’m going out tomorrow with my bra to start load development! Looking very forward to what it might be able to do as the fire forming loads were .2’s-.3’s with n140. Also finishing a load for the 223 with 70gr rdf’s and n140 at 3150fps range

 

[Matt_3479]

Well I got out today, did 2 ladder tests going up in charge then coming back down looking for poi and velocity similarities. I started getting pressure around 31/31.2 gr’s of n-140 and around 2950ish fps. I got it to 3000 fps but that’s with heavy bolt lift and flat primers and dare not to go past!
I loaded up the last 8 pieces of 30.4 after loading up my ladders (remaining prepped brass) and it provided avg 2905fps with an sd 4.4.

it seems I may have a node around 30.4-30.6 fps as they landed within 3/4” at 300 yards and 15fps es over the 4 rounds and another possible place too look at 31.2-31.4 as they landed in 1/2” at 300 yards with 3 in about 1/4” at 300 yards but the bolt lift is just entering into heavy, but primers don’t look bad. 31.2/31.4 is producing 2905 range and 31.2/31.4 is producing 2960fps range

 

[Jdne5b]

I may have missed it, but what brass did you end up going with, and what are your other rifle specs?

 

[JFrank]

Well I got out today, did 2 ladder tests going up in charge then coming back down looking for poi and velocity similarities. I started getting pressure around 31/31.2 gr’s of n-140 and around 2950ish fps. I got it to 3000 fps but that’s with heavy bolt lift and flat primers and dare not to go past!
I loaded up the last 8 pieces of 30.4 after loading up my ladders (remaining prepped brass) and it provided avg 2905fps with an sd 4.4.

it seems I may have a node around 30.4-30.6 fps as they landed within 3/4” at 300 yards and 15fps es over the 4 rounds and another possible place too look at 31.2-31.4 as they landed in 1/2” at 300 yards with 3 in about 1/4” at 300 yards but the bolt lift is just entering into heavy, but primers don’t look bad. 31.2/31.4 is producing 2905 range and 31.2/31.4 is producing 2960fps range

Can you post any pictures of your targets? Especially the upper node.

 

[Matt_3479]

I may have missed it, but what brass did you end up going with, and what are your other rifle specs?

I went with Lapua brass. This rifle is an impact 737r action, benchmark 26” mtu 1:7.5 twist, heathen brake, tt diamond, mpa ba comp. I have a ks heavy varmint 1:7.5 twist I’ll be spinning up as well.